DNA Encoding: It's not just for evolution anymore

Well, you did specify that it is not reversible. But my message was mostly just me being picky again. I do not want someone to read the thread here and get the wrong ideas. (I figured you already knew that anyway.)

The fact that you can with astronomical odds manage to get the same SHA-1 or MD5 hash with a different file means the hash system is far from perfect, but for general purposes it works out well enough. For those who do not know, many sites use CRC-32, MD5, and/or SHA-1 hashes to check the validity of a file. For instance if you download CCleaner or anything else on FileHippo, there is a MD5 checksum available to verify it with the right tools. (On the Technical tab of any application.)

To prove that "Astronomical Odds" are not actually impossible, check this file. Go ahead and extract it anywhere and check the files inside. It is an anomaly that has a tiny chance of happening, but *DID* happen in this case.

*Edit* To be more clear for those who do not get it, the zip inside is the *EXACT SAME SIZE AND CONTENTS* of the original. Even the checksums are identical.

 

Can either of you give me an example of a situation in which it isn't important that two parties have the contents of the message, but they need to know that they have the same message?

 

If we were working on a top-secret project and one of us asked the other a yes or no question and the other would typically answer yes or no to that, but this time answered "perhaps" or "Blueberries" or something else that is just plainly wrong, the first thing to do is determine if the message was intercepted and changed in some way. This hashing allows you to be certain within a majorly potent numeral of certainty that the message, whatever it may be is the correct one.

I can dream up dozens of not so espionage related examples too. Like the hashing of files on sites allows you to be certain that if the file is corrupt, it was that way before you got it if the hash checks correctly.

If Essential Skills mods came with a hash, I would bother to check it. But I am a nut about such things. I remember failed downloads from the dial-up days. The uncertainty of if the file was corrupt but downloaded correctly led me to redownload the same corrupt files several times before I gave up.

 

You made me think of the days when I'd be sitting in the computer room at a terminal, and some bozo would walk over and start tapping on the audio coupler (essentially, a primitive modem that was very sensitive to sound and vibration). You could see the garbage show up on the teletype in real time.

 

Let's say I send my bank a message that's encrypted. I really, really want to know that they got the exact same message as I sent, *but if they sent back the unencrypted message to double check, it would defeat the point*. So, they can send back a calculated hash, I can calculate the hash on my end, and if they match - well, I could have been duped, but its more likely that the bank got my message correctly.

This can also be used to defend against a man in the middle attack by using a known secure second communications channel (e.g. the phone) to exchange checksums.

Edit: Another addition is for changing passwords.

You want to have the same password 'known' to you and the service, but all you want to transmit is a hash.

 

Lol. Off topic, but I remember my massive bajillion character init string for my old 300 baud modem...

In those days, 300 baud was crazy fast. I doubt most people in the world even know the meaning of baud without a search engine to hold their hand.

On topic, today it sounds crazy that we may eventually replace magnetic platters and SSDs with DNA/RNA samples. But then when I was using that 300 baud I would think it was crazy to think that in my lifetime we would have cable connections that offered roughly a hundred thousand times the bandwidth. And we do today. I also would not believe that we could have wireless connectivity that was truly global. And in a sense we do now. (That last part can be picked apart if you like, but you get my point.)

 

Mining pretty much covered it all but the most ubiquitous use of cryptographic hashes is so that system administrators cannot easily recover passwords of the users on the system. An example would be this forum, it'd be pretty nasty if Derek could just get at all your passwords. The polite thing to do is only to ask the user for their hash and store that.

 

http://blogs.discovermagazine.com/80beats/?p=42546#.UQRXpldCyHt

Update with more info (or possibly something new):

Original article:

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11875.html

 

I am still quite skeptical. The fact is that no one cell can provide enough data storage for anything useful, so many must be used. But the problem here is how will you get to the desired parts without scanning the entire set into memory and decoding it? The best way is to set it into tiny packets of a few thousand cells and have each packet made up of parity archives, so that even if half is lost, with a 50% parity set, you can reconstruct with zero loss so long as the remaining 50% remains intact and usable.

The remaining problem is that tiny vials still take up massive amounts of space when you have a few thousand of them and they would have to be mechanically moved to the scanner/reader device one at a time. The vials would likely be 9/10ths the total size of the samples. (Even using wafer thin borosilicate glass with mylar coating to keep sunlight out.)

No real technical details are provided however. It reads to me like those mail-order flying car advertisements from a decade or two back.

The details I am concerned with are what temperatures, humidity levels, atmospheric pressures, magnetic fields, and other conditions can this retain full reliability in? Whenever they say nothing bad about something, I tend to think it must be *REALLY* bad. I hope I am wrong...

 

It's early in its development -- no one should be expecting a really practical application of anything so new so quickly in any case. As an example, I was reading about electronic paper and fuel cells, and the like YEARS before there were any commercial application of them. So it's too soon to make any rash judgements. You can choose to be skeptical, but keep in mind that this is not a mature technology. Give it a couple of years at least to see if there's any progress.

BTW, magnetic fields should be irrelevant for this (DNA is non-magnetic, as are nearly all organic chemicals, or at least all that I am personally aware of), But temperature I'm sure is a consideration -- cooler is better (heat leads to vibrating molecules, leads to entropy, which leads to errors). I doubt that humidity and atmospheric pressure would be too much of an issue, unless you are storing it under quite unusual conditions (eg. transporting it to Mars). It shouldn't be something any harder to protect than a hard drive, for example (and actually easier, taking everything into account).

 

But we DO have flying cars. We just happen to call them "Helicopters". I'm sure you CAN buy them through the mail also, if you have the money to do so.

 

Magnetic fields are irrelevant only when the strength of the field is too.

Remember homing pigeons. They sense magnetic fields, and certain insects cannot even move in a coordinated way when exposed to a potent field.
https://en.wikipedia.org/wiki/Magnetoception

In the atmosphere of the Earth, we are greatly, *GREATLY* shielded from magnetics that occur outside the atmosphere, A single near miss sunspot would make compasses spin for days or longer.

If Humans ever hope to leave Earth, or to survive a direct hit of a sunspot, however minor, we need to have a means to rebuild when we emerge from our deep, deep mines that we would have to hide in. Information is vital to that. And cannot be trusted to anything that would be blank the instant the atmosphere was mostly whipped off and the magnetism is hundreds of thousands of times as intense.

 

Magnetite has been discovered in many migratory birds, so that's the probable explanation. And magnetite is inorganic, plus it's not in DNA. How magnetite gets into the brains of migratory birds, I do not know, and at least back when it was a topic for discussion in geology classes, it was unknown how it got there. If anyone else knows, feel free to add to the discussion. But that's believed to be the explanation behind (at least the how) of navigation in migratory animals.

There were experiments going on at Caltech while I was there concerning the effects of strong magnetic fields on human beings, and continued experiments elsewhere over the years, whenever a new charge arises concerning power lines, etc. The effects of magnetism on living organisms is something that has been studied OVER AND OVER again. There's no evidence that strong magnetic fields have any significant detrimental affects on organic life (other than those that navigate via magnetic fields, and as I said, magnetite has been found in the brains of some of those animals).

 

BTW, here's a quote:
Naturally magnetic, biologically precipitated magnetite (Fe3O4) has been found in chitons, magnetotactic bacteria, honey bees, homing pigeons, and dolphins.

The mechanism is still unknown, but it's likely connected to this.

 

If you have a magnetic field sufficiently strong to ruin DNA (by fucking up individual electron orbitals), they're damn well strong enough to fuck us up by virtue of us having a non-zero amount of metallic substances inside of us.

 

Alright, an MRI uses a potent magnetic field, but is nowhere near potent enough to harm us. If you had your samples in the MRI for a year or two, would it be in any way effected? If no, then it is likely good enough to shut me up. But there is a whole list of things I worry about this being susceptible to.

Temperature is the biggest and most likely problematic one.

And as someone who has dealt with many tiny vials in my time, the odds of breaking one remain pretty high, so atmospheric pressure and contents are issues to be determined.

If for example you used a tiny sample with a tiny scanner as the backup OS for an ICBM and it was hit by a potent EMP from an airburst nuclear device, good thinking suggests it should start reading the backup OS immediately. But in little or very high atmosphere, the contents and pressure are radically different. Is there any reason to think the samples would be unaffected, or would that just be more wishful thinking?

Since no-one seems to be talking about a scanner device, I have to presume that at this time one does not exist and a microscope manned by a Human is doing the work. Whenever this changes we will have more to talk about. But for now all we can do is speculate. You all already know what general side I will be on in most any argument, so I will let you argue as you want here.

 

I think people are totally losing track of what the relevant question is. No one is arguing that you could not disrupt DNA (or atomic nuclei, for that matter) with a sufficiently strong application of energy of any kind. Hell, if you want to get totally ridiculous, why not argue that it's an impractical technology because it couldn't survive burning.

Your arguments are way off track. What we are talking about is NOT will it survive anything. The question is, will it survive normal storage conditions. And so far no one here has suggested that it won't. And btw, refrigeration and metal boxes as a condition is NOT unreasonable if the cost is low enough. Heck, no one here remembers how cold computer rooms had to be?

 

I think we are looking at this from two very different positions.

I am looking at this as a replacement of all existing magnetic storage. I can see retrofitting DNA/RNA on platters of a typical disc drive stripped of the magnetics. Then all you need is a scanner device small enough to work. That resolves the problem of how you get to the data you want. (Verses having to scan an entire volume of a vial into memory and discarding whatever is not wanted.

But the issue of how long it will last and in what conditions remains. You cannot put a typical hard drive, no-matter how well insulated on the space station, nor on a satellite. If this is all but invulnerable to the magnetic and low temperature issues that would destroy platter drives of today, then they could be used for those things.

The arguments are off track for the uses you are likely seeing. But I am looking to broad applications, and frankly I can hold a 4 terabyte drive in one hand with zero strain. Data density is not a problem here on the well shielded surface of the Earth.

So perhaps you now see a bit more of why I am obsessed with what this can endure before it decays?

Have you ever seen a robot built that can enter a heavily irradiated reactor room to effect repairs? No? That must be because there is no shielding that can protect the hardware from the massive energies that penetrate cubic feet of lead in minutes. I do not think this would be of any use in fixing that problem, but if it were resistant enough to allow the 'bot to work for a few minutes, then it could be driven on a tow line and reeled in when it died, for another to be sent.

The problem is that even ECC memory degrades fast in heavy radiation. But if it could be set to reboot from a DNA/RNA scanner every minute and start work again, the damage would be far less and it may be able to keep our aging nuclear eyesores stable for decades longer than at current. (As I am sure you know, they are burred in cement when they are beyond hope of repair. But they would still be lethally radioactive in a hundred thousand years.)

So while this is not relevant questions for desktop use, I do not think we have a need for this for desktop computers at the moment. So I am exploring the other possibilities.

 

We don't have ANY application at the moment. If there is an application for which it is well-suited, we won't know about until/if we find a way of making it practical in the first place. I'm just saying that it should not be dismissed out of hand.

Maybe it is a dead end, at least for the foreseeable future. I'm saying that maybe it's not.

As someone else pointed out, we already know that DNA is viable for data storage, simply because if it were not, life on earth would not exist, at least as we know it. The main question is, can it be harnessed for other purposes. I'm betting it can. The big question isn't whether it's possible, but whether it can be practical, and how soon will it be practical.

 

~50M of those HDDs of storage in the DNA in my hand. It's not 10-20x as much storage - it's 6+ orders of magnitude more.